Question: Simplify to lowest terms. $\dfrac{21}{18}$
What is the greatest common factor (GCD) of 21 and 18? $21 = 3\cdot7$ $18 = 2\cdot3\cdot3$ $\mbox{GCD}(21, 18) = 3$ $\dfrac{21}{18} = \dfrac{7 \cdot 3}{ 6\cdot 3}$ $\hphantom{\dfrac{21}{18}} = \dfrac{7}{6} \cdot \dfrac{3}{3}$ $\hphantom{\dfrac{21}{18}} = \dfrac{7}{6} \cdot 1$ $\hphantom{\dfrac{21}{18}} = \dfrac{7}{6}$